41
Servicing should only be performed by a Quali
fi
ed Service Technician
Model 500
Locate the throttle adjustment screw on top of the gas valve, see Figure 11. Using a screwdriver, turn the
screw a 1/4 turn counterclockwise to increase CO
2
levels or a 1/4 turn clockwise to decrease CO
2
levels.
After one adjustment on the valve, follow the Combustion Analysis Procedure on Page 39 of this Service
Handbook to measure the combustion.
If combustion is still not within the speci
fi
ed range, repeat the procedure. This procedure SHOULD NOT be
performed more than four (4) times. If after four (4) adjustments and the combustion is still not within the
speci
fi
ed range, revisit the possible causes in Table 13 on Page 39 or replace the gas valve.
Models 600 - 800
Locate the throttle adjustment screw on top of the gas valve, see Figure 12. Using an Allen wrench, turn the
screw a 1/4 turn counterclockwise to increase CO
2
levels or a 1/4 turn clockwise to decrease CO
2
levels.
After one adjustment on the valve, follow the Combustion Analysis Procedure on Page 39 of this Service
Handbook to measure the combustion.
If combustion is still not within the speci
fi
ed range, repeat the procedure. This procedure SHOULD NOT be
performed more than four (4) times. If after four (4) adjustments and the combustion is still not within the
speci
fi
ed range, revisit the possible causes in Table 13 on Page 39 or replace the gas valve.
Figure 11. Gas Valve Adjustment: Models 500
THROTTLE
ADJUSTMENT
SCREW
(REMOVE BLUE CAP)
Figure 12. Gas Valve Adjustment: Models 600 - 800
